The detective is playing godfather to a bewildered
young woman named Laurie, who's set upon by a fortune-hunting killer. She is the target of the title, sought after by a murderer called Blue.
Blue has killed Laurie's uncle Tully for gold and then is momentarily stumped to learn that the victim's property has been bequeathed to Laurie.
That's no problem, Blue tells himself, coz I'll just razzle-dazzle her, and if her fiance Lester makes trouble, well, two murders is the same as one, if I get caught.
But little does Blue realise that Barnaby and Tully were the best of friends and that our hero is godfather to Laurie.